ya, it's not like niacin flush which I've felt before. This was just intense itching mostly in the arms and legs. I took 1000mg in the day and then another 500mg in the middle of the night when it started. I gave it a break for awhile and tried 500mg yesterday and I was fine so I dunno.
Antihistamines did seem to help it and I just read there's a relationship between b3 and histamine tolerance. It's more of an issue with lack of b3, but maybe taking too much can have an effect too